1. Field of the Invention
The present invention relates to a control valve for variable-capacity compressor used in air conditioners of vehicles and the like and, more particularly, to a control valve for variable-capacity compressor controlling the supply of a coolant gas in the interior of a crankcase from a delivery-pressure region as required, which is characterized by means for adjusting and setting sensitivity in a pressure-sensitive part.
2. Description of the Related Art
Conventionally, variable-capacity compressors provided with a cylinder, a piston, a wobble plate, etc. have been used, for example, as disclosed in the Japanese Patent Application Laid-Open No. 9-268973, in compressing and delivering a coolant gas of an air conditioner for automobiles. A known variable-capacity compressor of the above-described type is provided with a coolant-gas passage that communicates with a delivery-pressure region and a crankcase, and configured so as to change the inclination angle of the wobble plate by adjusting the pressure in the interior of the above-described crankcase thereby to change delivery capacity. And for the pressure adjustment in the interior of the crankcase, there is provided means for supplying a high-pressure compressed coolant gas from the above-described delivery-pressure region to the above-described crankcase by the opening adjustment of a control valve provided within the coolant-gas passage.
And as the above-described control valve for variable-capacity compressor, there has been proposed a control valve in which for the adjustment of sensitivity in a pressure-sensitive part, means is provided to perform rotational operation by applying a tool (a screwdriver) to a screwdriver groove formed on the back portion of an adjusting screw (the Japanese Patent Application Serial No. 2001-108951). However, to adjust many control valves individually by use of tools requires not only tools separately, but also much labor and time, and there are cases where efficiency is low.
An object of the invention is to ensure that the sensitivity adjustment of a pressure-sensitive part which constitutes a control valve for variable-capacity compressor is simply and easily performed and that, furthermore, in making a sensitivity adjustment, sealing after the sensitivity adjustment can be positively performed.
Therefore, in order to achieve the above-described object, a control valve for variable-capacity compressor in the first phase of the invention comprises a control valve body, a solenoid excitation part, and a pressure-sensitive part having a pressure-sensitive element, wherein the sensitivity of the pressure-sensitive element can be adjusted by an adjusting screw provided so as to permit an adjustment of forward and backward movement with respect to a frame supporting the pressure-sensitive part, and the adjusting screw is rotationally operated by engaging an engagement part, which is annexed to a coil assembly constituting the solenoid excitation part, against the adjusting screw thereby to operate the coil assembly.
The control valve of the first phase can have the following features.
A connector of the solenoid excitation part is formed integrally with the coil assembly by use of a synthetic resin.
A bellows is disposed as the pressure-sensitive element, the frame supporting the pressure-sensitive part is constituted by an attraction element, and the bellows is expanded and contracted by means of an adjusting screw provided so as to permit an adjustment of forward and backward movement with respect to this attraction element.
The bellows is expanded and contracted by rotating the coil assembly or connector with respect to the attraction element.
According to the control valve for variable-capacity compressor in the first phase of the invention, by rotating the coil assembly with respect to the attraction element, the adjusting screw is rotated and the bellows is expanded and contracted, with the result that the sensitivity of the pressure-sensitive element can be adjusted. Furthermore, because the connector is integrally formed with the coil assembly, the rotation of the adjusting screw becomes easy. In addition, because the sealing capacity of the coil portion is improved, a fear of corrosion decreases.
A control valve for variable-capacity compressor in the second phase of the invention comprises a control valve body, a solenoid excitation part, and a pressure-sensitive part having a pressure-sensitive element, wherein the sensitivity of the pressure-sensitive element can be adjusted by an adjusting screw provided so as to permit an adjustment of forward and backward movement with respect to a frame supporting the pressure-sensitive part, and the adjusting screw is rotationally operated by engaging an engagement part, which is annexed to a coil assembly constituting the solenoid excitation part, against the adjusting screw thereby to operate the coil assembly. Furthermore, a solenoid housing is provided at an outer periphery of the solenoid excitation part, and for mounting the above-described coil assembly on this solenoid housing through an O-ring, a ring-mounting recess with a notched section is formed in an outer periphery of this coil assembly, and the solenoid housing opposed to this ring-mounting recess is provided with a lid part which is formed in an end of the solenoid housing through a bending part.
The control valve of the second phase can have the following features.
A plurality of projections digging into the coil assembly are formed in an edge portion of the lid part.
The frame supporting the pressure-sensitive part is constituted by an attraction element, and the bellows is expanded and contracted by means of an adjusting screw provided so as to permit an adjustment of forward and backward movement with respect to this attraction element.
The bellows is expanded and contracted by rotating the coil assembly or connector with respect to the attraction element.
According to the control valve for variable-capacity compressor in the second phase of the invention, by rotating the coil assembly with respect to the attraction element, the adjusting screw is rotated and the bellows is expanded and contracted, with the result that the sensitivity of the pressure-sensitive element can be adjusted. Furthermore, because the connector is integrally formed with the coil assembly and rotational operation can be preformed without giving a rotational force to the O-ring, the rotation of the adjusting screw becomes easy. In addition, because no irregularity occurs in the seal ring, the sealing capacity of the coil portion is improved and a fear of corrosion decreases.